1. Technical Field
This invention relates to the field of anthraquinone, fiber-reactive dyes.
2. Background
The present invention is directed to water-soluble, fiber-reactive anthraquinone dyes. The class of anthraquinone dyes is well known in the art. As a class, such dyes are generally considered to possess excellent fastness properties. However, as a class they suffer from the disadvantage of high raw material cost. It is therefore important in the industrial dyeing and printing of substrates for a dye to provide superior dye properties, and superior processing characteristics at a competitive cost.
U.S. Pat. No. 5,112,971 represents an attempt to produce improved anthraquinone dyes having fiber reactive moleties useful in dyeing or printing substrates containing hydroxyl and/or amide groups. The dyes of this prior art reference may be represented by the following formula: ##STR2##
The dyes of this invention provide dyed or printed substrates with excellent fastness properties. In addition, the dyes of the invention provide unexpectedly superior color yield and may be effectively employed in dyeing processes at low dye bath salt concentrations. This property of providing high color yield at low dye bath salt concentrations is an important advantage in that lower raw material costs are achieved at lower waste water purification costs. In addition, the use of less salt in the dyeing process is an important environmental advantage. A second environmental advantage is that the dyes of the invention provide brilliant violet shades without metal complexing the dye; i.e. they are free of heavy metals.